COHORT PERSPECTIVESIn another example, the influences of cohort
differences in norms has been analyzed as the
process of ‘‘cohort norm formation’’ (Riley 1978).
As members of a cohort respond to shared histori-
cal experiences, they gradually and subtly develop
common patterns of response, common defini-
tions, and common beliefs, that crystallize into
new norms and become institutionalized in alter-
ed social structures. For instance, over the past
century many individual women in successive co-
horts have responded to common social changes
by making many millions of separate but similar
personal decisions to move in new directions: to
go to college, have a career, or form their families
in innovative ways. Such decisions, beginning in
one cohort and transmitted from cohort to cohort,
can feed back into the social structures and gradu-
ally pervade entire segments of society. Thus, many
new age norms have become expectations that
women should work, and have stimulated the
demand for new role opportunities at work and in
the family for people of all ages.
Age Composition and Structures. At any giv-
en period of history, the coexisting cohorts of
people that form the age strata coincide with the
existing role structures (both indicated by the
perpendicular lines in Figure 1). People who differ
in age and experience confront the available age-
related opportunities, or lack of opportunities, in
work, education, recreation, the family, and else-
where. However, people and structures rarely fit
together smoothly: there is a mismatch or ‘‘lag’’ of
one dynamism behind the other.
Structural Lag. While people sometimes lag
behind structures as technology advances, more
frequent in modern society is the failure of struc-
tural changes to keep pace with the increasing
numbers of long-lived and competent people (Riley,
Kahn, and Foner 1994). Cohorts of those who are
young today have few ‘‘real-world’’ opportunities;
those in the middle years are stressed by the
combined demands of work and family; and those
who have reached old age are restive in the pro-
longed ‘‘roleless role’’ of retirement. Cohorts of
people now old are more numerous, better edu-
cated, and more vigorous than their predecessors
were in 1920 or 1950; but few changes in the places
for them in society have been made. Capable
people and empty role structures cannot long
coexist. Thus, implicit in the lag are perpetual
pressures toward structural change.
Age Integration. Among societal responses to
structural lag are current tendencies toward ‘‘age
integration’’ (Riley, Foner, and Riley 1999, p.338).
With pressures from the expanded numbers of
age strata, many age barriers dividing education,
work and family, and retirement are gradually
becoming more flexible. People of different ages
are more often brought together, as lifelong edu-
cation means that old and young study together, as
new entrepreneurships hire employees of mixed
ages, as in many families four generations are alive
at the same time, or as the age segregation of
nursing homes is replaced by home health care
with wide access to others. Where such tendencies
may lead in the future is not yet known. But the
interdependence between cohorts and structure
is clear.RESEARCH METHODS.When aspects of these broad cohort perspectives
are translated into empirical studies, a variety of
research methods are required for specific objec-
tives: from analyses of historical documents and
subjective reports, to panel analyses and mathe-
matical modeling, to rigorous tests of specific
hypotheses. This brief overview can only hint at
the diverse research designs involved in analyses
of the multiple factors affecting lives of people in
particular cohorts; or in the shifting role opportu-
nities for cohort members confronting economic,
religious, political, and other social institutions
(for one example, see Hendricks and Cutler 1990).Cohort Analysis. The tool most widely used in
large-scale studies is ‘‘cohort analysis,’’ which takes
the intercohort aging perspective—in contrast to
‘‘period analysis’’ (Susser 1969), which takes the
cross-sectional perspective. (The difference is illus-
trated in Figure 1 by comparison of the diagonal
cohort lines, in contrast to comparison of a se-
quence of vertical compositional slices). In his
1992 formulation of the technical aspects of co-
hort analysis, Ryder defines the term as ‘‘the pa-
rameterization of the life cycle behavior of indi-
viduals over personal time, considered in the
aggregate, and the study of change in those pa-
rameters over historical time’’ (p. 230). He concep-
tualizes the cohort as ‘‘providing a macro-analytic
link between movements of individuals from one
to another status, and movements of the popula-
tion composition from one period to the next.’’